Roche to Buy Santaris Pharma

Danish Biopharmaceutical Company Will Cost up to $450 Million

ZURICH—Roche Holding AG said Monday it was buying Danish biopharmaceutical firm Santaris Pharma for as much $450 million, as the Swiss giant looks for ways to develop drugs for diseases difficult to address with existing medicines.

Roche, based in Basel, Switzerland, said in a statement that it would make an initial cash payment of $250 million for privately held Santaris, which specializes in relatively new RNA-targeting...